Problem: $\left(-8x - 4\right)\left(x + 8\right) = \ ?$
Solution: $= -8x \cdot \left(x + 8\right) - 4 \cdot \left(x + 8\right)$ $= \left( -8x \cdot x \right) + \left( -8x \cdot 8 \right) + \left( -4 \cdot x \right) + \left( -4 \cdot 8 \right)$ $= -8x^2 + \left( -8x \cdot 8 \right) + \left( -4 \cdot x \right) + \left( -4 \cdot 8 \right)$ $= -8x^2 + \left( -64x - 4x \right) + \left( -4 \cdot 8 \right)$ $= -8x^2 - 68x + \left( -4 \cdot 8 \right)$ $= -8x^2 - 68x - 32$